In a so-called bell and spigot type pipe coupling, one pipe has a female end, or bell, for matingly receiving a male end, or spigot, of another pipe of like construction. Various types of gaskets have been provided over the years for preventing leakage between such pipes when coupled. Leakage is a particularly acute problem when large diameter pipes, such as 4 to 15 inch diameter sewer pipes, are coupled and their axes misaligned, either during assembly or as a result of subsequent soil shifting. While in situ methods of providing a leak resistant joint in such couplings, such as soldering metal pipes or glueing non-metal pipes, may be satisfactory in many applications, there has been a need for a gasket which permits a leakproof pipe joint to be made simply by sliding the pipes together endwise without regard to the precision with which they are aligned endwise.
Pipe gaskets which fit into interior grooves of bell and spigot pipe couplings enabling pipe ends to be slid together to form a leak resistant coupling are known. An example of such a gasket is disclosed in U.S. Pat. No. 4,487,421. A conventional pipe gasket for a typical bell and spigot pipe joint is illustrated in cross-section in FIG. 4 herein. While these pipe gaskets may have utility in certain applications, there is a continuing need for a gasket which provides a fluid tight seal, which can tolerate a certain amount of misalignment between the plates, and which can be installed in a labor efficient manner.